On 3/27/2015 3:44 PM, Greg Schmitz wrote:
> Here is a link to the original article:
> "Utilizing 3-D digital laser microscopy to image damaged optical media."
> By Greg Gogolin, James Jones, and Derek Brower
> On 3/27/15 10:33 AM, Steven Smolian wrote:
>> This is from the Ampex list. I thought some of the ARSC and MLA
>> would be interested as well.
>> Steve Smolian
>> -----Original Message-----
>> From: Ampex [mailto:[log in to unmask]] On Behalf Of
>> Bill Ruck
>> Sent: Friday, March 27, 2015 12:51 AM
>> To: Ampex Mailing List
>> Subject: [AMPEX] Survival
>> Saw this today in the March 2015 issue of Laser Focus World. (Yes,
>> I do read strange magazines.)
>> Olympus microscope recovers data from damaged optical media
>> Designed for nanometer-level imaging and 3D measurements, the LEXT
>> laser-scanning confocal microscope from Olympus (Center Valley, PA) can
>> provide both visual and height maps of damaged CD and DVD optical
>> media (or
>> acute-angled specimens) and recover data from that media using custom
>> algorithms. With a 405 nm wavelength source, the LEXT OLS4000 has a
>> magnification range from 108X to 17,280X and dedicated objective
>> lenses with
>> high numerical apertures.
>> To obtain usable information from damaged optical media (both
>> factory-pressed and home-burned CDs and DVDs), a highly magnified
>> image of
>> the damaged media is created and a region of consecutive dots and
>> dashes is
>> selected. Although the dots and dashes appear to form concentric
>> they actually form a spiral, so there are no beginnings and endings
>> to the
>> apparent tracks. Each dot and dash is then quantitatively measured.
>> Next, the encoding algorithm used to convert the original data into
>> dots and
>> dashes is reversed. (There are only a handful of encoding algorithms in
>> wide use, and most of these are publicly
>> available.) Even if severe data impact has occurred (significant
>> chemical alterations, surface destriction, or even a disc broken into
>> multiple pieces), it is still possible to adjust the algorithms to
>> data based on measurements obtained by the OLS4000.
>> So it seems to me that the guys now recovering audio from strips
>> coated with
>> iron rust need to invest in something like this for optical media.
>> Bill Ruck
>> San Francisco
>> Ampex Mailing List
>> [log in to unmask]
>> Copyright 2015 by the author of the post.
>> Sent: [log in to unmask]